/* Copyright 203-2115 AtomWare Technology Pty Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 * The flowing information must be keep 
 * GroupBy.java
 * wholebasic
 * 2013-6-18上午9:47:54
 * @author 屈甲康
 * QQ285799123
 * mailto:qujiakang@gmail.com
 */

package org.jackysoft.query;

import java.util.Collection;
import java.util.List;
import java.util.ListIterator;

import org.apache.commons.lang3.StringUtils;
import org.springframework.util.CollectionUtils;

import com.google.common.collect.Lists;

/**
 * query aider to help collect sql group by condition
 * 
 * @see Order
 * 
 * **/
public class GroupBy extends Aggregation {

	/**
	 * 
	 */
	private static final long serialVersionUID = -8658457757411177168L;
	protected List<QueryField> havings = Lists.newArrayList();
	private List<Aggregation> names = Lists.newArrayList();

	public GroupBy() {
		super();
	}

	public List<QueryField> getHavings() {
		return havings;
	}

	public void setHavings(List<QueryField> havings) {
		this.havings = havings;
	}

	public List<Aggregation> getNames() {
		return names;
	}

	public void setNames(List<Aggregation> names) {
		this.names = names;
	}

	public String groupString() {
		Collection<String> gstr = Lists.newArrayList();
		for (Aggregation name : names) {
			gstr.add(name.aggregate(null));
		}

		if (gstr.isEmpty())
			return "";

		return " group by " + StringUtils.join(gstr, ',') + this.havingString();

	}

	protected String havingString() {

		if (CollectionUtils.isEmpty(havings))
			return "";

		String qs = "";
		org.apache.commons.collections.CollectionUtils.filter(havings,
				new EmptyQueryFieldPredicate());
		ListIterator<QueryField> litr = havings.listIterator();

		int size = havings.size();
		for (; litr.hasNext();) {
			QueryField qf = litr.next();
			if (qf == null)
				continue;
			int nidx = litr.nextIndex();
			if (nidx == size) {
				qf.setNoOutOpr(true);
			}
			qs += qf;
		}
		if (StringUtils.isBlank(qs))
			return "";
		return " having " + qs;
	}

}
